Hydraulic systems with straight pipeline connecting a hydraulic pump to change-over valves are used widely in laboratory devices and apparatus. Since there is a need for numerical prediction of the dynamic characteristics of transition flow, secondary modelling of the mathematical model for two-dimensional and slightly compressible viscous flow results in a more simple numerical prediction method for laminar transition flow and a computer software is developed. Hydraulic shocks generated in hydraulic systems of laboratory devices and LHD are calculated with computer. Experiment verification and simulation analysis of dynamic characteristics proved the effectiveness of the numerical prediction method and the relevant software, and revealed the transient change law of oil transition flow so that a new inspection method for hydraulic systems is provided. Finally, the expected profits and application prospect of this study evaluated.